This invention relates to an automatic developing apparatus for a photosensitive material, and more particularly to a rapid processing automatic developing apparatus or a compact automatic developing apparatus which has been improved to effectively prevent oxidation or deterioration of processing solutions, and which provides troublesome free cleaning maintenance of conveyance rollers.
Conventional automatic developing apparatus for processing photosensitive materials such as photographic films and papers, range from a large-sized apparatus such as a large-sized central processing installation, which will herein be referred to as a large-sized laboratory, to a comparatively small size apparatus used in a small shop, which will herein be referred to as a minilaboratory. Further small-sized developing apparatuses are also concerned, well-known types being a self-service developing apparatus to process a direct positive photograph by use of identification cards and so forth, a developing apparatus to process X-ray films, and a super small-sized developing apparatus which includes manual operation.
In conventional automatic developing apparatus, it is common to store processing solutions in processing tanks, convey the photosensitive materials to the processing tanks using a conveyance rack or a guide plate and so on, and to process the photosensitive materials by dipping them in the processing solution in the tank. This may be referred to as the immersion processing system.
In the case of comparatively small-sized automatic developing apparatus, there are variations on the immersion processing system. They are: processing photosensitive materials by conveying them through a processing solution stored in a tubular processing tank; conveying photosensitive materials horizontally with the photographic emulsion side downward in order to contact them with processing solutions; coating processing solutions on the photographic emulsion side with rollers; and spraying processing solution over the emulsion side from below.
When a processing solution is left exposed to air, it reacts with oxygen in the air to become oxidized and deteriorated, and thereby the processing efficiency of the solution is seriously affected.
In a large-sized automatic developing apparatus, a processing tank can store a large quantity of a processing solution, which is more than 10 liters. The ratio of the surface area of the solution to the quantity of the solution is small, and a large open space is left in the top of the processing tank after a lid is put in place.
In a small-sized automatic developing apparatus, when the quantity of solution stored in the tank is more than 4 liters, which is comparatively large, the same countermeasure as for the large-sized automatic developing apparatus can be applied, or a floating lid can be set on the upper surface of the solution as disclosed in Japanese Patent Publication Open to Public Inspection No. 27968/1979.
This invention aims at a small-sized developing machine which stores less than 2 liters of solution in its processing tank. In this case, the ratio of the surface area of the solution to the quantity of the solution is large. Whereas in conventional apparatuses, even if a lid is put on the top of the storage tank, the processing solution continues to be oxidized by the air existing between the lid and the surface of the solution. For that reason, for instance, as shown in U.S. Pat. No. 3,273,485, Japanese Patent Publication Open to Public Inspection No. 28338/1985, and so forth, a method is proposed in which the processing solution stored in a processing tank is fed to a tubular tank and photosensitive materials are conveyed through the tube to be processed. As disclosed in U.S. Pat. No. 3,330,196, a method is proposed in which the processing solution is soaked up by coating rollers and coated on photosensitive materials.
In the case of conventional automatic developing apparatus where processing solution is stored in the processing tank and photosensitive materials are conveyed by a conveyance rack or a guide plate to be dipped in the solution, i.e. the immersion processing system, the solution adheres to the photosensitive materials, and transfers to conveyance rollers located at the delivery side of the processing tank and the adhered solution hardens when the apparatus is not used. The solution adhered to the rollers affects processing efficiency and normal conveyance of photosensitive materials when the apparatus is next operated.
Therefore, in a conventional large-sized automatic developing machine, maintenance is necessary, such as taking apart the conveyance rollers before or after operation and cleaning them with water.
In order to reduce troublesome roller cleaning work, in an automatic developing apparatus known as PCC, for example the Color Seven Copy Machine manufactured by Konica; the following method is adopted. First of all, a cleaning roller is set to come into contact with a conveyance roller with pressure, and dirt on the conveyance roller is transferred to the cleaning roller. In an automatic developing apparatus for an X-ray film, a method to convey a cleaning paper through the conveyance rollers in advance to remove dirt from them, is in practical use. A method to wind a cleaning paper round the conveyance roller, is proposed.
Recently, minilaboratories are spreading. As a result, it is possible to pick up finished phtos within an hour at some DPE (developing, printing, and enlarging of phtographs) shops. In spite of the appearance of these minilaboratories, about 75% of films and photographic papers are processed at large-sized laboratories.
However, in the case of a large-sized laboratory, there is a limit to the reduction of its finishing time because collection and delivery are conducted through agents. If minilaboratories spread widely in the future, super rapid processing in which all processing is finished within an hour, will become a common concept and it is thought that many films and photographic papers will be processed at minilaboratories.
When we survey the future, it is thought that the technology of automatic developing apparatus will advance from processing at a minilaboratory to self-service DPE processing, in which a small-sized automatic developing apparatus similar to office automation equipment will be used.
In this kind of processing system, an automatic developing apparatus must be located not only at specialty stores like the conventional minilaboratories, but also at various places where office automation equipment is located. Accordingly, it is anticipated that the automatic developing apparatus will have to be smaller than the minilaboratory used now.
The minilaboratory which is used now is pretty large although it is called small-sized. Therefore it cannot be located in a small store, and it requires skilled operation. An operator must be skillful at treating photosensitive materials and processing solutions, at adjustment work when a jam occurs in the apparatus, and at maintenance work, such as cleaning of rollers and filters. As expressed above, the minilaboratory can not be installed in a small shop because of space limitations and skill restrictions.
The requirements for an automatic developing apparatus to be used in a future processing system are that it must be super small-sized and light, maneuverable, simple in its mechanism and troubleproof. Furthermore, the requirements for the apparatus are that it uses a small quantity of processing solution, it discharges small amounts of waste fluid and waste matter, it smells as little as possible, it seldom causes vibration, it scarcely make a noise, and it can be manufactured at a reasonable cost.
The inventors earnestly studied and improved the automatic developing apparatus to meet the requirements explained above and succeeded in completing the present invention. The first object of the invention is to reduce the amount of processing solutions to be as little as possible and to effectively prevent processing solutions from oxidization and deterioration, which are particularly remarkable when the quantity of solution is small.
The inventors further conducted a diverse investigation and found that when the conveyance speed of photosensitive materials to be processed is less than 5 cm/min, maintenance of the conveyance rollers is not necessary, but when the speed is 5 cm/min to 100 cm/min, cleaning maintenance of the conveyance rollers is indispensable.
Thus, the second object of the present invention is to provide an automatic developing apparatus, the conveyance rollers of which are easily cleaned for maintenance. Other and further objects, features and advantages of the invention will appear more fully from the following description.
The following description concerns the third problem. In the category of comparatively smaller sized automatic developers, there is an application example of soaked-in processing method, whose technology (i.e., solution is stored in the processor tank or bath formed in a slit, and photographic sensitized material or photosensitive material is transported through this slit for processing in contact with solution) was publicized in the Patent Disclosure (Japanese Patent Publication Open to Public Inspection) No. 131138, 1988.
It is mentioned in the disclosure that with this technology, deterioration of solution is minimized because the [aperture area "S" on the solution surface/processor tank capacity "V"] ratio is small. This invention of which aperture section is designed in a slit (thin) to comply with the cross section of sensitized material, however, presents such a drawback that the size of the auto developer cannot be made smaller because an amazingly lengthy processor tank (to increase "V") is required in order to lessen the aperture area "S". Meanwhile, an attempt to reduce the size of machine (that is, to decrease "V") is accompanied by the need of making the aperture area "S" at the entrance of material extraordinarily smaller, plus, by another problem (for instance, crystallized substance will be readily separated, or scratches will be readily produced on photographic sensitized material). Especially when processing a thin, lengthy material such as color film, there was detected a critical defect that the processing performance for the material results in completely differing between `immediately after` the processing start and `just prior` to its end. Further, if the treatment is carried out employing the same solution as used in a large-sized auto developer, the use of a machine based on a slit-shaped tank was found out to necessitate a longer period of processing time in order to obtain the same performance to the large-sized unit. It was concluded that such slit-tank unit is not suitable for speedy processing.
Another example of this type of slit-tank unit is found in the Patent Disclosure No. 259661, 1988. With this technology, the material transport speed in the tank is faster than the flow of solution, further, the solution flow and the material transport are in opposite directions. The solution newly supplied comes in contact with the material transported in opposite directions at the exit of the tank, but because the movement direction of the solution and material is reversed, the liquid surface level in a narrow slit-tank unit loses stability, in other words, in many cases, the solution overflows. Accordingly, it is difficult to keep the surface level stabilized. Meanwhile, when the leading portion of the material enters the slit tank, a resistance is caused against the direction of transport, then, it was found that the resistance, provides a disorder such as jamming because the material is not transported smoothly. Another significant drawback was recognized in terms of assured material transport, particularly when treating "thin type" ones such as a film base with the thickness less than 150 .mu.m of a color paper with the thickness less than 200 .mu. m
A technology concerning this kind of developer is publicized in the U.S. Pat. No. 3,273,485. In case of this developer, an extra tank connected to such type of thin, lengthy slit-shaped processing tank, is provided under the processor unit, and if the solution is not used for a longer period, it can be stored in the extra tank.
With this technology, however, there is a drawback that the remaining solution attached in the slit tank is solidified and crystallized objects are generated. As the same in the case of the technology stated in the Patent Disclosure No. 131138, 1988, the slit structure of its tank offers such drawbacks as irregularity in development, desilvering and rinsing, and unappropriateness for use in speedy treatment. It was found in conclusion that this technology is not suitable for development of photo sensitized materials.
In addition, the Patent Disclosure No. 178965, 1989 publicizes a sensitized material treatment device equipped with a shallow developing tank and an extra tank filled with the solution shut out from open air, and incorporating a circulation means to permit solution circulation between the processing tank and the extra one. As this unit utilizes a shallow tank, the aperture area in the upper portion of the tank cannot help being designed larger in size, thereby causing a problem of deterioration in solution. As a remedial measure, a floating lid is provided to avoid oxydization of solution. Yet, it still presents such a drawback that a thin membrane is formed on the float by the solution whenever the float fluctuates because a perfect hermetically sealing measure is not taken, which might easily "accelerate" further oxydization. Especially when treating with a small volume of solution, deterioration of the solution becomes remarkable.
Compact design of each tank may realize miniaturization of the developing unit itself, but if it should end in adversely affecting photographic performance of treated materials, the importance of photography itself would be lost. There exists a number of factors to give influence on photographic performance. In the invention concerned which has a structure of substantial, hermetical sealing, the important points are, among others, the agitation effect and accuracy of temperature control of the solution in the processor tank. Meanwhile, as more compact design of auto developer is achieved, the volume of solution is reduced that much. In this regard, the point is how to maintain solution stability against various kinds of deterioration, for instance, caused by oxydization or evaporization-originated incrassation.
Further, treatment of silver halide photographic sensitized materials should be carried out in total darkness. Unit miniaturization would make, however, the solution supply port and material removal port far closer in distance to the processing tank, causing a difficulty to maintain an appropriate property of light shielding in the processor.